Hydraulically operated variable pitch marine screw propeller



Feb. 19, 1957 V c, HARVEY 7 2,781,857

HYDRAULICALLY QPERATED VARIABLE PITCH MARINE SCREW PRQPELLER Filed April 14, 1954 3 Sheets-Sheet l fizz-acidic EEO/[m INVE/VTQ'? GEORGE C. H/I/PVI/ L; O O 0 O )7 577K): I 1 M ATmR/w'xs Feb. 19, 1957 I G. c. HARVEY 2,781,857 HYDRAULICALLY OPERATED VARIABLE PITCH MARINE SCREW PROPELLER Filed April 14, 1954 3 Sheets-Sheet 2 INVENTOQ' G-EORG-F C. HAR V)/ Feb. 19, 1957 Filed April 14, 1954 e. c. HARVEY 2,781,857 HYDRAULICALLY OPERATED VARIABLE PITCH MARINE SCREW PROPELLER 3 Sheets-Sheet 3 INVENTOR George C. Harvey BY W MOQNEYJ HYDRAULICALLY OPERATED VARIABLE PITCH MARINE SCREW PROE'ELLER George C. Harvey, Kegworth, Derby, England, assignor to Slack & Parr (Marine) Limited, Derby, England Application April 14, 1954, Serial No. 423,089

4 Claims. (Cl. 170-160.32)

This invention relates to hydraulically operated variable pitch marine screw propellers and is concerned with the control gear for such propellers by means of which the pitch variation of the blades is effected.

in certain constructions of control gear for hydraulically operated marine screw propellers the propeller shaft is located axially in the hull of the vessel by a thrust bearing and pitch-changing of the blades is effected by a member arranged coaxially of the propeller shaft and which rotates therewith. This coaxial member extends with the propeller shaft into the hull of the vessel and is capable of having forward and rearward axial movement, relatively to the propeller shaft, positively imparted to it by suitable hydraulic control means. It is with this general character of hydraulic control gear that the present invention deals.

According to the invention hydraulic control gear of the aforesaid character is provided wherein the thrust bearing serves to locate the propeller shaft both axially and radially with respect to an element which is fixed angularly and longitudinally relatively to the hull of the vessel, said element also serving as a means for transferring hydraulic fluid from an external source of supply to the hydraulic control means which effects axial movement of the aforesaid member.

Preferably operation of the hydraulic control means is governed by movement of a valve carried by the element, such valve controlling flow of the hydraulic fluid through channels formed in the element.

By the provision of a single element combining the thrust block of the vessel and the control valve of the control gear, such element also serving as a transfer means for hydraulic fluid to the latter, a construction of control gear results which is more compact and therefore simpler to install than those hitherto employed, since less length is required in the engine room. Moreover it is cheaper to produce, more robust in construction, and simpler to line up than the known constructions The aforesaid element, with which the thrust bearing is combined, may be located both angularly and longitudinally with respect to the hull of the vessel, for example by attaching it rigidly to a fixed part of the hull and/or the engine casing. Thus the element may be bolted or otherwise rigidly secured to bearers carried by the hull, to the rear end of the engine casing or alternatively to an extension of the engine bearers.

The thrust bearing may be of any suitable type such as roller, ball, collar or Michell.

A preferred construction of the control gear will now be described, by way of example, with reference to the accompanying drawings, in which:

aired States Patent ice Figures 1a and 1b are views, partly in plan and partly in section, of the forward end of the propeller shaft and the element by which it is located with respect to the hull, Figure lb at the left hand side joining as a continuation with the right hand side of Figure la and the section part of both views being taken on the line lib-1b of Figure 2,

t Figure 2 is a cross-sectional view of the parts shown in Figure lb taken on the line 22 of that figure in the direction of the arrows, and

Figure 3 illustrate-s diagrammatically a rear portion of the hull of a vessel with the propeller shaft in position therein.

Referring to the drawings, the propeller shaft comprises a hollow tubular rear portion 5 which extends from the propeller 6 into the hull 7 of the vessel towards the engine, an intermediate portion 10 having a coaxially formed bore 10a! and provided with an external coupling 11 by which it is coaxially secured to the rear portion, and a forward substantially solid portion 12. The latter extend-s between the intermediate portion 10 and the engine itself and at its forward end carries an externally flanged cylindrical coupling 13 by which it is connected to the engine, the coupling 13 being held by a nut 14 against a shoulder 15 formed on the shaft. The ad jacent ends of the portions If 12 of the shaft are provided with radially projecting flanges 16, 17 respectively which are connected to each other by an annular cylindrical member 18 in a fluid-tight manner so that an operating chamber or cylinder 19 for a hydraulic piston 20 is formed between the adjacent ends of the shafts.

The aforesaid member arranged coaxially of thepropeller shaft and by axial movement of which relatively to the latter pitch variation of the blades is effected is in the form of a control rod 21 slidably arranged in the bore Ida of the intermediate portion of the propeller shaft, the radially reduced front end 21a of the control rod projecting forwardly through the operating cylinder 19 between the adjacent ends of the shafts and entering a coaxial bore 22 formed in the rear end of the forward portion 12 of the propeller shaft. The hydraulic piston 29 in the cylinder 19 divides the latter into front and rear spaces 19a, 19b and the piston is fixedly secured on the portion 21b of the control rod which traverses the cylinder between a shoulder 23 formed on such portion and a nut 24 so that movement of the piston forwardly or rearwardly in the cylinder actuates the control rod 21 and effects variation of the pitch of the propeller blades.

Two spaced thrust bearings 25, 26 are arranged on the forward portion 12 of the propeller shaft, the inner races 25a, 26a of such bearings being axially located on the shaft by means of shoulders 27 formed on the latter and the coupling 13 against which the inner races are held by screw rings 28. The outer races 25b, 26b of the thrust bearings, which are preferably of the taper roller type and act also as radial bearings for the shaft 12, are located one towards each end of a hollow sub stantially cylindrical element or casing 2 coaxial with the forward portion of the propeller shaft, such outer races being held in place against shoulders formed on the inner cylindrical surface of the element by annular end caps 31 secured to the element by bolts 32. Such endv caps project inwardly into close proximity with the shaft 12, the gaps between the latter and the inner peripheries of the end caps being rendered fluid-tight by suitable sealing rings 33.

Location of the element 29 both angularly and longitudinally with respect to the hull of the vessel is effected by means of feet 29a formed on the outer surface of the element which extend diametrically outwards therefrom and are secured to longitudinal bearers 8 fixedly carried by transverse bearers 9 attached to the hull 7 of the vessel. Alternatively or additionally provision may be made to attach the element to the rear end of the engine casing. Besides forming the thrust block for the propeller shaft the element 29 also serves as a means for transferring hydraulic fluid from an external source of supply to the hydraulic cylinder 19 between the intermediate and forward portions 10, 12 of the propeller shaft. An oil pump, not illustrated, driven either by the main engine of the vessel or an auxiliary source of power feeds hydraulic fluid under pressure by means of a pipe 34, Figure 2, to the central portion of a piston-type hunting valve mounted in a housing 36 on the upper external surface of the element 29. Such valve admits hydraulic fluid to one or other of two axially spaced channels 37, 38 drilled radially in a thickened central portion 39 of the element 29 and from these channels the oil passes through regis tering channels 40, 41 drilled in a sleeve 42 running on the forward portion 12 of the propeller shaft to axially spaced annular grooves 43, 44 formed in the inner surface of the sleeve. The two pairs of registering channels 37, and 38, 41 form the coarse and fine pitch oil feeds and suitable sealing rings 45 are provided between the element 29 and sleeve 42 and between the latter and the shaft 12 to separate the respective feeds and prevent leakage therefrom.

From each of the annular grooves 43, 44 formed in the sleeve 42 hydraulic fluid is conducted by channels formed in the forward portion 12 of the propeller shaft to the hydraulic cylinder 19 at the rear end thereof. Fluid from the front annular groove 43 passes by way of a radial channel 46 drilled in the shaft to a forward extension 47 of the coaxial bore 22 therein, thence through a short bore 48 in the forward end of the control rod 21 to a radial channel 49 in the rod which emerges from the surface thereof on the rear side of the piston 20 into the rear space 1% of the hydraulic cylinder 19. Hydraulic fluid is supplied to the front space 19a of such cylinder by way of two diametrically opposed radial channels 50, drilled in the forward portion 12 of the shaft and the outer ends of which are aligned with the rear annular groove 44, and two diametrically opposed axial channels 51 extending to the rear end of the shaft 12.

The projecting end 350 of the hunting valve 35 is operated by a cam, not illustrated, controlled through a differential coupled both to the propeller control lever and the piston 20 in the hydraulic cylinder 19. Connection of the differential to the piston 20 is effected by means of an annular member 52 slidably mounted on the forward portion 12 of the propeller shaft adjacent the flange 17 at the rear end thereof. The piston 20 is connected to the member 52 by rods 53 angularly spaced about the axis of the shaft 12 which pass in a fluid-tight manner through holes 54 drilled in the flange, the member having a circumferential groove 55 formed on its outer periphery which cooperates with a finger of the fork of the diflercntial. To prevent any possible tendency of the piston 20 to rotate in the cylinder 19 guide rods 56 on which the piston slides are provided, such rods being secured at each of their ends in holes formed in the flanges 16, 17.

If desired, additional channels may also be incorporated in the element, for purpose of water cooling.

I claim:

1. Hydraulic control gear for a variable pitch marine screw propeller comprising in combination a hollow propeller shaft on the outer end of which the propeller is mounted and which extends inwardly into the hull of the p all] vessel, a control member arranged coaxially within said propeller shaft to rotate therewith and axial movement of which relatively to the propeller shaft effects pitchchanging of the propeller blades, said control member extending with the propeller shaft into the hull of the vessel, hydraulic control means for positively effecting axial movement in both directions of said control member relatively to the propeller shaft, an element operatively connected to said propeller shaft, bearers secured to the hull which carry said element, means for attaching said element to said bearers to angularly and longitudinally fix said element to the hull of the vessel, a thrust earing for said propeller shaft carried by said element and which locates the propeller shaft both axially and radially with respect to said element and therefore with respect to the hull of the vessel, and a control valve incorporated with said element for governing the supply of hydraulic fluid to said hydraulic control means, said element serving as a means for transferring hydraulic fluid from an external source of supply to said hydraulic control means to enable the latter to effect axial movement of said member.

2. Hydraulic control gear for a variable pitch marine screw propeller comprising in combination a hollow pro peller shaft on the outer end of which the propeller is mounted and which extends inwardly into the hull of the vessel, a control member arranged coaxially within said propeller shaft to rotate therewith and axial movement of which relatively to the propeller shaft effects pitchchanging of the propeller blades, said control member extending with the propeller shaft into the hull of the vessel, a piston operatively associated with said control member to effect axial movement in both directions of the latter relatively to the propeller shaft, :1 cylinder for said piston and carried by the propeller shaft so as to be coaxial therewith, an element which surrounds the propeller shaft, bearers secured to the hull which carry said element, means for attaching said element to said bearers to angularly and longitudinally fix said element to the hull of the vessel, a thrust bearing for said propeller shaft carried by said element and which locates the propeller shaft both axially and radially with respect to said element and therefore with respect to the hull of the vessel, and a control valve incorporated with said element for governing the supply of hydraulic fluid to said cylinder, said element serving as a means for transferring hydraulic fluid from an external source of supply to said cylinder to opposite sides of said piston to enable the latter to effect axial movement of said member.

3. Hydraulic control gear for a variable pitch marine screw propeller according to claim 2, wherein said cylinder is arranged between the propeller and the element and the propeller shaft comprises at least two portions the rearmost of which has a bore formed therein carrying said control member, said cylinder comprising an annular cylindrical member and the cylinder and piston being interposed between adjacent flanged ends of said two portions of the propeller shaft.

4. Hydraulic control gear for a variable pitch marine screw propeller comprising in combination a hollow propeller shaft on the outer end of which the propeller is mounted and which extends inwardly into the hull of the vessel, a control member arranged coaxially within said propeller shaft to rotate therewith and axial movement of which relatively to the propeller shaft effects pitch-changing of the propeller blades, said control member extending with the propeller shaft into the hull of the vessel, a piston operatively associated with said control member to effect positive axial movement in both directions of the latter relatively to the propeller shaft, a cylinder for said piston and carried by the propeller shaft so as to be coaxial therewith, a substantially cylindrical element, adjacent said cylinder, which surrounds the propeller shaft, bearers secured to the hull, means for at taching said element to said bearers to angularly and References Cited in the file of this patent UNITED STATES PATENTS Fedden Jan. 5, 1943 Hoover Apr. 18, 1944 Martin Mar. 20, 1945 Fielding Dec. 8, 1953 FOREIGN PATENTS Great Britain June 18, 1952 

